Ductwork is often used to convey conditioned air (e.g., heated, cooled, filtered, humidified, dehumidified, etc.) discharged or drawn from a blower and to distribute the air to a room or other areas within a building. Ducts are typically formed of sheet metal, such as steel, aluminum, or stainless steel. In some installations, a muffler or duct silencer is added to reduce noise often associated with sheet metal ducts. Other air ducts, however, are made of pliable materials, such as fabric or flexible plastic sheeting. Examples of pliable ducts are disclosed in U.S. Pat. No. 6,425,417, which is incorporated herein by reference in its entirety.